Pneumatic supports in the form of inflatable hollow bodies are known in several variations, for example, from U.S. Pat. No. 3,894,307 (D1) and WO 01/73245 (D2) of the same applicant as the present application. If such a support is subjected to a transversal load, the primary objective consists of absorbing the occurring tensile forces and shearing forces without causing the support to buckle.
In D2, the axial compressive forces are absorbed by a compression member while the axial tensile forces are absorbed by two tension elements that are helicoidally wound around the hollow body and fixed on the ends of the compression member. The pneumatic portion of the structural elements described in this publication has the function of stabilizing the compression members against buckling.
In D1, several hollow bodies are combined in a parallel fashion so as to form a bridge. In this case, the tensile forces are absorbed by a flexible cover that encompasses all hollow bodies, and the compressive forces are absorbed by the bridge plate that is composed of strung-together elements. The elements are laterally fixed on the cover that encompasses the hollow bodies and thusly secured against buckling.
D2 is the document most closely related to the present invention. The pneumatic structural element disclosed in D2 contains at least two tension elements that are relatively long in comparison with the length of the structural element due to their helicoidal arrangement around the hollow body. Under a load, this leads to a more significant deflection than in instances, in which shorter tension elements are used. When such an element is used as a support, the nodes for absorbing the bearing forces which lie on top of the structural element rather than on the outermost end thereof require complicated bearing constructions. In D1, the tension element consists of a large-surface cover that is only able to absorb tensile forces to a limited degree and can only be stretched with a significant technical expenditure.
The invention is based on the objective of developing pneumatic supports with tension and compression members that have a high flexural strength, can be manufactured in a simple and cost-efficient fashion and easily assembled into complex structural components and structures, for example, roofs and bridges, wherein these structural components and structures can also be erected very quickly and easily connected to conventional constructions.
With respect to its essential characteristics, the solution to this objective is disclosed in the characterizing portion of claim 1, wherein other advantageous embodiments are disclosed in the succeeding claims.